Self-priming pump



Nov. 4, 1947.

Filed March 25, 1944` 3 Sheets-Sheet l sse Z Z 7K. Curti/s.

Nov. 4, 1947.

` F. w, HEcKER'r Erm.

SELF-PRIMING PUMP Filed March 25, 1944 3 Sheets-Sheet 2 v www? J/E/7 7 5 Frederick [Il fzecter.

Patented Nov. 4, 1947 SELF-PRIMING PUMP Frederick W. Heckert and Russell R. Curtis, Dayton, Ohio,- assignors to Curtis Pump Company,

` Dayton, Ohio, a corporation of Ohio Application March 25, 1944, Serial No. 528,022 9 Claims. (Cl. 103-113) Thisinvention relates to a self-priming pump containing a centrifugal pump assembly and a positive displacement pump assembly for priming the centrifugal'pump assembly.

Specifically the invention deals with a compact, portable electric motor driven self-priming fuel servicing pump especially Well adapted for the rapid refueling or defueling oi aircraft.

The invention will be hereinafter specifically described as embodied in a portable pump and motor unit that is compact but operates at high speed and has high delivery capacity, but' it should be understood that the principles of the invention are applicable to pumps for other purposes Vincluding fixed permanently mounted Pumps.

Refuelingand defuellng of aircraft, especially military aircraft, must frequently be accomplished at places where regulation pumping equipment is not available. Therefore, a compact, lightweight pump and motor unit adapted to be driven by the batteries of an airplane, and carried in the airplane as an accessory, is highly desirable.

Centrifugal pumps can be driven at very high speed and will have a higher delivery capacity than a positive displacement pump of corresponding size and weight. However, centrifugal pumps do not have material suction capacity unless the pumping chambers thereof are filled with liquid. Such pumps must therefore either be primed or receive liquid under pressure orlhydraulic head.

To remedy the defects of high capacity centrifugal pump assemblies, the present invention provides a positive displacement pump for priming the centrifugal pump. The rotor of the positive displacement pump is preferably mounted on the same shaft carrying the impeller of the centrifugal pump. Since the positive displacement pump is only intended as a primer, it need not have high pumping capacity and therefore can'be t 4made very small and light in weight.

It is, thus, an object of the invention to provide a small, compact lightweight self-priming pump and motor unit especially suited as an aircraft accessory for fueling and defueling of the aircraft fuel tanks. y

A further object of the invention is to provide an electric motor and pump unit wherein a single shaft carriesk the rotor of a positive displacement priming pump and the impeller of a centrifugal pump.

A still further object of the invention is to provide a pump and motor unit wherein a centrifugal pump has a central inlet and an annular pumping chamber with an impeller capable of drawing liquid through the inlet and centrifugally discharging the liquid through the pumping chamber into an outlet, and wherein the pumping chamber is primed by means of an adjacent rotary vane type Dump.

Another object of the invention is to provide a multiple pump unit wherein the pumping chamber of one pump is primed by an adjacent pump.

. A stiu further object of the invention is to pro- `vlde a self-priming centrifugal pump and motor unit.

A specific object of the invention is to provide a compact, portable electric motorpositivedisplacement primer pump-centrifugal type main pump unit having high capacity.

A still further object of the invention is to provide a high speed self-priming pump assembly wherein a rotary vane type pump operates with a centrifugal pump of greater capacity and serves to prime the centrifugal pump.

` Other and further objects of the invention will. be apparent to those skilled in the art from the following detailed descriptions of the annexed sheets of drawings, which illustrate a preferred embodiment of the invention.

On the drawings:

Figure 1 is a longitudinal vertical cross-sectional view with parts in side elevation, of a portable self-priming pump and motor unit according to this invention.

Figure 2 is a transverse vertical cross-sectional view, with parts in elevation, taken along the line II-II of Figure 1.

Figure 3 is a fragmentary enlarged vertical cross-sectional view of a portion of the pump assembly taken along the line III--III of Figure 5.

Figure 4 is a horizontal cross-sectional view, with parts in plan, taken along the line IV-IV of Figure 1. s

Figure 5 is an enlarged vertical cross-sectional view, with parts in end elevation, taken along the line V-V of Figure 4.

Figure 6 is a fragmentary vertical cross-sectional View taken along the line VI-VI of Figure 5.

As shown on the drawings:

In Figure 1 the reference numeral l0 designates generally a portable, self-priming pump and electric motor unit including an electric motor casing ll with a flanged end l la, a positive displacement pump casing I2 having a flanged end |2a secured to the portion Ila of the motor casing Il, a centrifugal pump casing I 3, and a cover I4 for the casing bolted to a flange I2b of the casing I2 by means of thru bolts I5.

A cradle I6 supports the unit I0 and is secured to the motor casing II by means of a band I1 having eye ends such as I1a receiving pins I8 passed through legs I6a of the cradle I6 and carrying a clamping nut and bolt assembly I9 at the top end thereof for drawing the band I1 tight around the casing I I to secure the cradle I6 on the casing. A plug housing 20 is provided on the casing II to receive an energizing wire for the electric motor in the casing (not shown).

A carrying handle 2I has a pair of legs 2Ia (Fig. 4) depending therefrom in front of the flange I2a of the casing I2 and secured to the unit by means of screws 22 which extend through the fiange I2a into the flange IIa to also connect the casing I2 onto the casing I I.

As shown in Figure 1, the motor inthe casing II has a drive shaft with an internally splined socket head 23 receiving an externally splined head 24a of a pump shaft 24. This pump shaft 24 extends completely through the casing I2 into the casing I3.

The casing I2 has an end face I2e receiving thereagainst the flange of a cap member 25 through which the pump shaft projects. This cap member 25 has a pilot portion 25a fitting into the cylindrical part of the casing I2 and abutting a graphic carbon seal disk or ring 26 in the casing. A liner sleeve 21 is disposed in the casing and holds a packing ring or gasket 28 against a face of the disk 26 to seal the disk around the periphery thereof in the casing I2.

As shown in Figure 1, the disk 26 has a bore 26a therethrough through which the shaft freely projects and a chamber 29 is provided receiving the shaft therethrough between the disk 26' and the end cap 25. Top and bottom bosses 30 are provided on the casing I2 adjacent the flanged end I2a thereof and the pilot portion 25a of the end cap and these bosses 30 are bored-to provide ports 30a for draining the chamber 29 in the event that gasoline leaks past the seal disk 26.

A rotating seal member 3| is mounted on the shaft 24 and is urged by a spring 32 into sliding sealing contact with the disk 26;

The shaft 24 has bushings 33 therearound riding in plain carbon bearings 34 which are seated in the cylindrical part of the casing and held in spaced opposed relation by a liner sleeve 35. This liner sleeve 35 is held against rotation in the casing by means of a locking pin S which extends into an axial slot 35a in the outer face of the sleeve. The shaft 24 is thus rotatably mounted in the bearings 34. It will be noted that the casing I2 hasan end wall or shoulder I2d receiving a bearing 34 thereagainst, and that the liner 35 holds the other bearing 34 in proper spaced relation from the first bearing. The spacer sleeve 21 is bottomed on the second bearing 34 and the seal disk 26 is bottomed by the spacer sleeve. Therefore the pilot portion 25a of the end cap, in thrusting against the disk 26, serves to hold all of the internal pump parts in the casing, in proper thrusting relation with eachother.

The shaft 24 has a slotted rotor 36 secured thereon between the bearings 34 and pumping vanes 31 are slidably mounted in the slots of the rotor 36 to fly out under the'influence of centrifugal force when rotated and ride on the inner Wall of the liner 35 to act as pumping vanes. As shown in Figures 1, 4 and 5, the cylindrical casing I2 has an enlarged housing portion I2e extending around the top and sides thereof adjacent the flange IZb. This enlarged part I2e terminates in spaced relation from the flanged end I2a and is connected to said flanged 'end I2a by means of reinforcing ribs I2f. The top rib I2f merges with the top port boss 30 as shown in Figure 4 while, as shown in Figure l, no' bottom rib I2f is provided. The ribs I2f therefore extend between the fianged end I2a and the enlarged housing part I2e on the sides of the casing I2 and extend from the top port boss 3U and the housing part I2e on the top of the casing I2. No bottom rib is provided.

As best shown in Figure 5, the housing I2e defines an inlet chamber A and an outlet chamber B on opposite sides of the pumping chamber provided by the liner 35 in the cylindrical portion I2 of the casing. This pumping chamber in the liner has an inlet port 38 cut through the liner and the casing I2 to connect the chamber A with the pumping chamber 39 between the liner and rotor 36. An outlet port 40 is cut through the liner 35 and casing I2 to join the pumping chamber 39 with the outlet chamber B.

A raised portion I2g on the housing I2e provides an outlet passageway 4I for the chamber B.

As shown in Figure l, the cover I4 for'the casing I3 defines a central inlet I4a and has a depen-ding outwardly flared skirt portion I4b cooperating with the casing to define an annular pumping chamber 42 surrounding the inlet I4a.

'A centrifugal impcller 43 is mounted on the portion of the shaft 24 that projects into the casing and has pumping vanes 44 thereon defining pumping channels connecting the inlet I4a with the pumping chamber 42 to centrifugally throw liquid from the inlet 4into the pumping chamber and force the liquid through the pumping chamber to a peripheral discharge passageway 45 provided by an upstanding nipple casing portion I3a. y

As best shown in Figure 2 the upstanding casing portion Ita also defines a passageway 46 alongside of the lpassageway 45. A seat 41 is provided by the casing portion I 3a around the mouth of the passageway 45 an-d a flap valve 48 cooperates with the seat 41 to close the passageway 45. The valve 48 is in the form of a disk 48a (Fig. 4) with a central pin 48h projecting through a lever arm 48e and secured therein by means of a cotter pin. The lever arm 48e is pivoted on a pin 48d carried by a bracket 48e secured in the passageway 4G.

As best shown in Figures 2 and 3, the passageway 4I from the chamber B communicates with the passageway 46,

A conduit tting 49 is bolted on the upstanding casing part I3a and defines a common passageway 5B communicating with the passageways 45 and 46 and large enough to accommodate swinging movement of the valve 48 away from its seat 41.

As best shown in Figure 2, the pumping chamber 42 adjacent the o-utlet passageway 45 thereof has a port 5I. This port 5l communicates with the interior of a screen in the chamber A as best shown in Figure 6.

As best shown in Figures 5 and 6, a screen unit 52 is formed from end plates 53 and 54 having flanges 53a and 54a therearouncl. These plates 53 and 54 are elongated and have tapered side walls converging from an enlarged rounded head portion to a smaller rounded tail portion.

A screen 55 is wrapped around the flanges 53a and 54a of the plate and is secured thereon as An end portion 55a of the screen 55 wrappedl around the flanges 53a and 54a is turnedupwardly and trimmed to provide an upstanding rib projecting above the screen unit 52 to facilitate mounting of the unit in position in the chamber A.

As shown in Figures '4, 5 and 6.v the housing portion |26 above the chamber A has a rectangular opening therethrough closed by .a cover 51 with a raised localized head portion 51a acted on by a lever 58 which is pivoted at one end to ears 59 on the top of the housing portion I2c and receives a swing bolt 60 through the other end thereof. The swing bolt 6D is pivoted on ears El formed on the side wall of the housing part I2e. A wing nut E2 threaded on the swing bolt 5U forces the lever 58 against the dome 51a to secure the cover 51 in sealing relation with the housing part I2a for closing the opening in the top of the chamber A. The cover can lbe removed by releasing the wing and nut and swing bolt from the lever 58 and the screen unit 52 is readily removable from the chamber for cleaning purposes. f

The portable unit of this invention therefore has a positive displacement type priming pump and a centrifugal type main pump driven by a single drive shaft from an electric motor. The pumping chamber of the centrifugal pump communicates through a port and screen with the inlet side of the positive displacement pump.

in full communication with the pumping chamber 42 While the outlet passageway 4| is in full communication with the discharge fitting 50.

From the above descriptions it will be understood that the invention provides a mixed now centrifugal pump assembly and a positive displacement priming pump assembly driven on the same shaft from a single electric motor. The entire unit is compactly arranged, is lightweight, and portable to provide a highly desirable acces sory for an airplane. The priming pump has sufficiently high suction capacity to draw air through the impeller of the centrifugall pump untilliquid is drawn into the centrifugal vpump The discharge side of the positive displacement pump communicates with the discharge conduit from the pumping chamber of the centrifugal pump which conduit is closed off from thepumping chamber -by a valve. The valve prevents the positive displacement pump from exerting suction in the conduit so that all intake suction during the priming of the main pump is exerted on the inlet of the main pump.

The unit operates by the positive displacement pump drawing air through the impeller of the centrifugal pump into the pumping chamber of this pump and thence through a port and screen into and through the pumping chamber of the positive displacement pump from which it is then exhausted on the discharge side of a flap check valve. The exhausting of the feed line by the positive displacement pump eventually draws fuel or other liquid received by the feed line into the 4impeller of the centrifugal pump to prime the pump and cause the discharge of the liquid through the flap valve. Once the pumping cham- -ber of the centrifugal pump is filled with liquid this centrifugal pump will be primed and will continue to pump liquidto the discharge fitting 50. The pumping capacity of the priming pump is very small, being the order of about one-tenth of the capacity of the centrifugal pump.

When the centrifugal pump is primed and operating to pump liquid, full discharge pressure of the centrifugal pump is maintained on both the inlet and outlet sides of the positive displacement priming pump, since the inlet port 5l is to fill the pumping chamber thereof and thus prime the pump so that it becomes an effective suction pump.

It will, of course, be understood that various details of construction maybe varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the-appended claims.

We claim as our invention:

1. A portable compact pump and motor unit comprising a motor casing, an electric motor therein, a priming pump casing mounted on an end face of the motor casing, a centrifugal pump casing mounted on the priming pump casing, a shaft extending into both casings drivingly connected to said motor, a rotary vane type pump in said priming pump casing having a vaned rotor mounted on said shaft, a centrifugal pump impeller in said centrifugal pump casing mounted on said shaft, said centrifugal pump casing hav`- ing a central inlet, an annular pumping chamber communicating with the inlet and a peripheral outlet, a discharge conduit mounted on the outlet part of the centrifugal pump casing, said priming pump casing having an inlet including the pumping chamber of the centrifugal pump for said motor casing, a clamping band securing said support to said motor casing, an electric motor in said motor casing, a rst pump casing secured to an end face of the motor casing, a second pump casing secured to an end face of the first pump casing, a handle projecting above said motor casing secured to said motor casing, a pump shaft extending through said first and second pump casings, means coupling said pump shaft to said electric motor for corotation, a vaned rotor on said pump shaft in said first casing, a centrifugal impeller on said shaft in said second casing, said first casing providing a pumping chamber for vsaid vaned rotor, said second casing providing a pumping chamber for said impeller, means directly connecting said pump chamber of the second casing with the inlet side of the pump chamber of the first casing, and means providing a common outlet for both pumps,

said vaned rotor pump being effective to prime said centrifugal pump.

3. A pump and motor unit comprising an electric motor having an elongated annular casing with a flanged end face, a cradle support embracing the bottom portion of said casing, band means securing said cradle support on said casing, a. positive displacement pump casing having an end face thrusting against the anged end face of the motor casing, a handle for said unit, bolts extending through the flanged end face of the pump casing and the flanged end face of the motor casing and through the handle for securing both casings and the handle in assembled relation, a centrifugal type pump casing mounted on the end of the positive displacement pump casing, means defining passageways connecting said pump casings, the inlet and outlet of said positive displacement pump being connected to the peripheral outlet of the centrifugal pump, and pumping means in the pump V`casings to prime the centrifugal pump casing and to pump liquid through-'the primed casing.

4. An aircraft accessory comprising an electric motor having a casing therearound, an end head on said casing, a priming pump casing bolted on said end head, a main pump casing on the end of the priming pump casing, a support secured on the motor casing holding the casing in horizontal position with the pump casing above the ground line, pumping elements in said priming pump casing for priming the main pump casing and for high capacity pumping of liquid through the main pump casing, and valve means in the peripheral outlet of said main pump which bypasses said priming pump.

5. A pump assembly comprising a cylindrical pump casing having a fully opened end, and an inturned shoulder at the other end providing a reduced opening therethrough, a pump shaft projecting through the cylindrical casing, a first -shaft bearing bottomed on said shoulder supporting said shaft, a pump liner bottomed on the rst shaft bearing, a second bearing bottomed on the liner, a spacer sleeve bottomed on the second bearing, a seal ring bottomed on the spacer sleeve, an end cap on the fully opened end of the casing having a pilot portion projecting into the casing and thrusting against the seal ring to hold the spacer sleeve, the bearings, and the liner in assembled relation, a housing surrounding the top and sides of the cylindrical casing and defining separated inlet and outlet chambers for the casing, said liner and said casing having ports therethrough communicating with said chambers, a vaned rotor on said pump shaft between said bearings for pumping liquid from the inlet chamber to the outlet chamber, a removable cover on the inlet chamber, said inlet chamber having a port, a screen in said inlet chamber suspended from said port, and said outlet chamber having an outlet passageway.

6. A pump assembly comprising a cylindrical pump casing, pumping elements in said casing, housing means surrounding said casing defining inlet and outlet compartments, said casing having inlet and outlet ports therethrough communicating with said compartments, a centrifugal pump mounted on an end wall of said casing having an .annular pumping chamber, a port directly connecting the annular pumping chamber of the centrifugal pump casing with the inlet chamber, a screen in said inlet chamber receiving fluid from said port, a removable cover for said inlet chamber giving access to said screen, said centrifugal pump casing having a peripheral outlet, a ilap valve for opening and closing said outlet, a discharge conduit receiving iluid from said outlet and ap valve, and housing structure defining a passageway connecting the outlet chamber with the conduit on theA discharge side of said flap valve. l

7. In a pump assembly a pump 'casing having an inlet chamber with an open top wall and a ported side wall, a readily removable cover for closing the open top of the casing, spring means, and a hollow screen unit having a flanged end face projecting into and resiliently held against said port by said spring means to suspend the unit from the port so that all iiuid entering the cham ber through the port must flow through the screen unit.

8. In a pump assembly means defining a pump chamber, a cover for closing the pentop of said chamber, said chamber having an end Wall with an inlet port therein, a screen unit having an end wall with an inlet port defined by a projecting collar, a second end wall on said screen unit having a projecting collar, a coil spring acting on said second end wall of the screen unit seated in said projecting collar for urging the rst mentioned collar into said port, and a screen-removing tab readily accessible through the open top of said casing to remove the screen unit.

9, A screen unit for a pump comprising a first end wall having an aperture therein with a projecting collar around the aperture, a second end wall having a projecting collar thereon, flanges around said end walls, and a screen wrapped around said flanges connecting said end walls in spaced relation and defining a hollow screen unit, said collar around the aperture of the first end wall adapted to be seated in a port, and said ccl-v lar on the second end wall adapted to receive the end of a spring, and a readily removable top wall for providing easy access to and removal of said screen unit.

FREDERICK W. HECKERT. RUSSELL R. CURTIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,187,031 Decker et al June 13, 1916 1,474,708 Drysdale Nov, 20, 1923 1,805,450 Harvey May 12, 1931 1,894,165 Drysdale Jan. l0, 1933 1,958,065 Paasche May 8, 1934 2,024,703 Ragsdale et al Dec. 17, 1935 2,046,904 Morgan July 7, 1936 2,113,923 Miller Apr. 12, 1938 2,150,125 Nelson Mar, 7, 1939 2,153,360 Auger et a1. Apr. 4, 1939 2,166,530 Morgan July 18, 1939 2,287,344 Easton et al. June 23, 1942 2,292,896 Morgan Aug. l1, 1942 FOREIGN PATENTS Number Country Date Great Britain June 13, 1940 

